Hello!
The Desert Storm Commemorative shown above is an interesting example of how the final price of an M9 could be influenced by more collectors all interested on the same item.
Back in 2006, this very same bayonet was sold for $ 128.50
http://www.quarterbore.net/forums/showthread.php?t=751.
In 2009 the price went to $ 1500.
To be honest, I think that what I paid for this M9 was really insane and not justified at all..... but I wasn't just able to find one.